const assert = require('assert')
const { once } = require('events')

module.exports = inject

function inject (bot) {
  const Item = require('prismarine-item')(bot.registry)

  let editBook
  if (bot.supportFeature('editBookIsPluginChannel')) {
    bot._client.registerChannel('MC|BEdit', 'slot')
    bot._client.registerChannel('MC|BSign', 'slot')
    editBook = (book, signing = false) => {
      if (signing) bot._client.writeChannel('MC|BSign', Item.toNotch(book))
      else bot._client.writeChannel('MC|BEdit', Item.toNotch(book))
    }
  } else if (bot.supportFeature('hasEditBookPacket')) {
    editBook = (book, signing = false, hand = 0) => {
      bot._client.write('edit_book', {
        new_book: Item.toNotch(book),
        signing,
        hand
      })
    }
  }

  async function write (slot, pages, author, title, signing) {
    assert.ok(slot >= 0 && slot <= 44, 'slot out of inventory range')
    const book = bot.inventory.slots[slot]
    assert.ok(book && book.type === bot.registry.itemsByName.writable_book.id, `no book found in slot ${slot}`)
    const quickBarSlot = bot.quickBarSlot
    const moveToQuickBar = slot < 36

    if (moveToQuickBar) {
      await bot.moveSlotItem(slot, 36)
    }

    bot.setQuickBarSlot(moveToQuickBar ? 0 : slot - 36)

    const modifiedBook = await modifyBook(moveToQuickBar ? 36 : slot, pages, author, title, signing)
    editBook(modifiedBook, signing)
    await once(bot.inventory, `updateSlot:${moveToQuickBar ? 36 : slot}`)

    bot.setQuickBarSlot(quickBarSlot)

    if (moveToQuickBar) {
      await bot.moveSlotItem(36, slot)
    }
  }

  function modifyBook (slot, pages, author, title, signing) {
    const book = Object.assign({}, bot.inventory.slots[slot])
    if (!book.nbt || book.nbt.type !== 'compound') {
      book.nbt = {
        type: 'compound',
        name: '',
        value: {}
      }
    }
    if (signing) {
      if (bot.supportFeature('clientUpdateBookIdWhenSign')) {
        book.type = bot.registry.itemsByName.written_book.id
      }
      book.nbt.value.author = {
        type: 'string',
        value: author
      }
      book.nbt.value.title = {
        type: 'string',
        value: title
      }
    }
    book.nbt.value.pages = {
      type: 'list',
      value: {
        type: 'string',
        value: pages
      }
    }
    bot.inventory.updateSlot(slot, book)
    return book
  }

  bot.writeBook = async (slot, pages) => {
    await write(slot, pages, null, null, false)
  }

  bot.signBook = async (slot, pages, author, title) => {
    await write(slot, pages, author, title, true)
  }
}